This invention relates to a microprocessor based control system which provides optimal field and armature currents to control a separately excited direct current (DC) motor.
The use of microprocessor control for the purpose of independently controlling the field and armature currents in direct current motors to achieve maximum efficiency is described in an article by Soon Chan Hong and Min Ho Park in IEEE Transactions on Industrial Electronics, Vol IE-34, No. 4, November 1987.
One problem with microprocessor or computer control of separately excited motors results from the fact that the field flux expected from a given field current, as derived from the motor equations employed, is not always as expected. The actual field flux will differ due primarily to magnetic hysteresis in the field poles; thus, while the theory may predict optimal motor performance under given torque and speed conditions, in reality, the resulting efficiency is often less than expected or desired.